A C-terminal PDZ domain-binding sequence is required for striatal distribution of the dopamine transporter

Nat Commun. 2013;4:1580. doi: 10.1038/ncomms2568.

Abstract

The dopamine transporter mediates reuptake of dopamine from the synaptic cleft. The cellular mechanisms controlling dopamine transporter levels in striatal nerve terminals remain poorly understood. The dopamine transporters contain a C-terminal PDZ (PSD-95/Discs-large/ZO-1) domain-binding sequence believed to bind synaptic scaffolding proteins, but its functional significance is uncertain. Here we demonstrate that two different dopamine transporter knock-in mice with disrupted PDZ-binding motifs (dopamine transporter-AAA and dopamine transporter+Ala) are characterized by dramatic loss of dopamine transporter expression in the striatum, causing hyperlocomotion and attenuated response to amphetamine. In cultured dopaminergic neurons and striatal slices from dopamine transporter-AAA mice, we find markedly reduced dopamine transporter surface levels and evidence for enhanced constitutive internalization. In dopamine transporter-AAA neurons, but not in wild-type neurons, surface levels are rescued in part by expression of a dominant-negative dynamin mutation (K44A). Our findings suggest that PDZ-domain interactions are critical for synaptic distribution of dopamine transporter in vivo and thereby for proper maintenance of dopamine homoeostasis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amphetamine / pharmacology
  • Animals
  • Behavior, Animal / drug effects
  • Binding Sites
  • Biological Transport / drug effects
  • Carrier Proteins / metabolism
  • Cell Cycle Proteins
  • Dopamine / metabolism
  • Dopamine Plasma Membrane Transport Proteins / chemistry*
  • Dopamine Plasma Membrane Transport Proteins / metabolism*
  • Dopaminergic Neurons / drug effects
  • Dopaminergic Neurons / metabolism
  • Endocytosis / drug effects
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / metabolism
  • Immunohistochemistry
  • Locomotion / drug effects
  • Mice
  • Mice, Knockout
  • Mutation / genetics
  • Neostriatum / drug effects
  • Neostriatum / metabolism*
  • Nuclear Proteins / metabolism
  • PDZ Domains*
  • Phenotype
  • Presynaptic Terminals / drug effects
  • Presynaptic Terminals / metabolism
  • Protein Binding / drug effects
  • Structure-Activity Relationship

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • Dopamine Plasma Membrane Transport Proteins
  • Nuclear Proteins
  • Prkcabp protein, mouse
  • Slc6a3 protein, mouse
  • Amphetamine
  • Dopamine